Relatively large refuse containers which are employed commercially are typically fabricated from steel and provided with a hinged lid which may be metal or plastic. These containers are usually stored outside and are exposed to the elements. Because the containers are made of steel, there is a tendency for the containers to rust, particularly in harsh environments such as coastal areas. In addition, the containers are heavy, making them difficult to transport and to handle.
These commercial refuse containers typically can hold a substantial volume of refuse, for example, in excess of 1.5 cubic meters (2 cubic yards). In order to provide lifting mechanisms for the refuse trucks, metal sleeves are attached to the container side walls to provide front loading refuse containers and/or a trunnion bar can be attached to the top of the front wall of the container to provide a rear loading container. With the metal containers, these lifting members are typically attached by welding or bolting.
Recently, attempts have been made to fabricate long lasting commercial size refuse containers from plastic materials. In the front load containers made from plastic materials, special structural modifications have been made to the container side walls where the lifting sleeve is attached in order to prevent tearing of the lifting sleeve away from the side wall. Additionally, because of the stresses expected to be applied to the container walls during the lifting operation, the containers have been fabricated from special plastic materials.
For example, U.S. Pat. No. 4,550,849 to Adsit discloses a commercial size plastic refuse container formed of a cross-linked polyethylene by rotational molding. A pair of metal lifting sleeves are in situ molded into the container side walls. The metal sleeves are disposed interiorly of the side walls of the container and are surrounded by plastic, and thus cannot readily be replaced; moreover, the container must be formed by rotational molding. The cross-linked polyethylene forming the container is used to ensure container strength, but this plastic cannot readily be recycled. In this regard, the plastic is shaped prior to initiation of the cross-linking process; thereafter, the cross-linking reaction permanently sets the shape of the molded plastic. Because the shape is permanently set by the cross-linking reaction, the plastic material cannot be recycled by heating and melting once the useful life of the container has ended.
U.S. Pat. No. 3,669,485 to Stihler discloses an open-top refuse container fabricated from fiber reinforced, hard resinous material. The end walls are provided with extra reinforcing layers so that lifting channels can be removably bolted to the side walls. Typically, glass reinforced plastics are fabricated from thermosetting plastic material and, like the cross-linked polyethylenes, these materials cannot readily be recycled.
Because of the potential durability and weight benefits which can be achieved by fabrication of commercial-size waste containers from plastic materials, substantial effort continues to be directed to the provision of such containers as evidenced by the above patents and similar commercial products. However, when cross-linked and thermosetting resins are employed to achieve the structural requirements necessary for the large containers, these containers, themselves, contribute to the growing world-wide waste problem. However, the conditions under which these containers are stored and used and the lifting operations used to empty the containers, have dictated in the past, the use of such special plastics.